Device for screwing and unscrewing screws, bolts and nuts

Abstract

Device for screwing and unscrewing screws, bolts and nuts comprising an electric motor (2), a flywheel (14) fixed on an auxiliary shaft (5) connected to the output shaft of the electric motor by means of a pair of pinions (3, 4) made of elastic plastic material like polyurethane and a wrench (9) connectable to said flywheel by way of projecting teeth (15, 16) and moving axially in relation to said flywheel by way of an elastic member (11).

I claim: 
     
       1. Device for screwing and unscrewing screws, bolts and nuts comprising a case (1) an electric motor (2) provided with an output shaft and inserted in said case (1), a first pinion (3) pressure assembled on said output shaft, an auxiliary shaft (5) having a first end and a second end, said auxiliary shaft being mounted at said first end on said case (1), a wrench (9) forming a seat (8) wherein said second end of said auxiliary shaft is engaged, a second pinion (4) pressure assembled on said auxiliary shaft (5), said first pinion engaging said second pinion, said first and second pinion being made of plastic elastic material, a flywheel (14) connected to said auxiliary shaft and driven thereby, said wrench (9) being connectable to said flywheel (14) and moving axially in relation thereto by means of elastic means (11). 
     
     
       2. The device according to claim 1 wherein said pinions (3, 4) are made of polyurethane. 
     
     
       3. The device according to claim 1 wherein said flywheel (14) is provided with a projecting driving tooth (15) and said wrench (9) is provided with a projecting tooth (16), said teeth (15, 16) engaging each other during rotation of said flywheel and when the wrench (9) is moved axially toward said flywheel. 
     
     
       4. The device according to claim 3 wherein said wrench (9) has an inner end and an outer end and is provided at said inner end with a flange (9b) said projecting tooth (16) being fixed on said flange. 
     
     
       5. The device according to claim 1 wherein said case (2) has a plate (7) fixed thereon, said plate has a seat (6) and said auxiliary shaft (5) is mounted on said case (2) by engaging in said seat (6). 
     
     
       6. The device according to claim 1 which comprises an invertor switch (17) and an electronic device (18, 19) adapted to power said motor (2) with a direct or limited voltage. 
     
     
       7. The device according to claim 6 which is provided with a LED (24) which lights up when said flywheel (14) reaches rated operating speed. 
     
     
       8. The device according to claim 1 which has a front space and a rear space and which is provided with service lamp (28) in a lower position thereof, said service lamp having a beam directed toward said front space.